ON THE CICHLID FISHES OF LAKE NYASSA. 675 



36. The Cichlid Fishes of Lake Nyassa. Bj C. Tate Regan, 

 M.A., F.R.S., F.Z.S., Keeper of Zoology, British 

 Museum (Natural History), 



[Received June 7, 1921 : Read June 7, 1921.'i 

 (Plates I.-YI.* ; Text-figures 1-30.) 



The Fishes of Nyassa have been somewhat neglected in com- 

 parison with those of Tanganyika and Victoria. They were first 

 described by Giuither (P. Z. S. 1864) from specimens collected 

 by Sir John Kirk, and nearly thirty years had passed before 

 the same author again described fishes from the lake sent by 

 Sir Harry Johnston (P. Z. S. 1893). Later a collection made 

 by Captain E. L. Khoades was described by Boulenger (Ann. & 

 Mag. N. H. (8) ii. 1908). In Boulenger's ' Catalogue of African 

 Fresh-water Fishes,' iii. (191.5), 38 species of CichlicUe are recorded 

 from ISTyassa ; one of these, Petrochromis vyassce, may now be 

 removed from the list. The supposed occurrence of the specialized 

 Tanganyika genus JBetrochromis in Nyassa was difiicult to 

 explain; re-examination of the type of P. nyasste leads me to 

 regard it as identicnl with the more recently described 

 P. fasciolatits, and I have no doubt that the locality assigned to 

 it was an error on the part of the collector. The loss of this 

 species from the Nyassa list is made good by the re-establishruent 

 of Gunther's Chromis suhocidcms, placed by Boulenger in the 

 synonymy of C, johnstoni, so that the number of valid species of 

 Cichlidse hitherto described from Nyassa is 38. 



The present revision is based on an examination of the speci- 

 mens in the collection of the British JNIuseum (Natural History), 

 including the types of all the species described by (xiinther and 

 by Boulenger, but principally on the study of a very fine collection 

 made and presented to the Museum by Mr. Rodney C. Wood. 

 As a result, the number of species is more than doubled, 46 being- 

 described below as new to science. Of the 84 species all but 5 

 (3 Tilajna, 1 Astatotilcqna, 1 Serranochromis) are endemic, and 

 the proportion of endemic genera is high, 11 out of 15, but more 

 than half the species belong to the widely distributed o-enus 

 Haplochromis. The majority of the Nyassa genera are quite 

 distinct from any found elsewhere : for example, Rhamphochromis, 

 which may be supposed to occupy the same place in Nyassa that 

 Bathyhates does in Tanganyika, is very difi'erent from Bathyhates. 

 There are, however, a few remarkable examples of conve)'gent 

 evolution in Nj-assa and Tanganyika t. The fish described below 

 as PseudotrO'pheus trojyheops bears a great superficial resemblance 

 to Tropheus. and has the same peculiar dentition ; another new 

 type, Aulonocara, has deep channels with large openings in the 

 frontal, nasal, orbital, prpeopercular, and mandibulary bones, 

 exactly as in Trematocara. 



* For explanation of the Plates see p. 727. 



t For the Tanganyika genera see Regan, Ann. & Mag. N. H. (9) v. 1920, p. 33, 



